A hammer is a tool that can be used to help you build something or to take something down, depending on its usage. To dream of a hammer could indicate a desire to create something, particularly something that is sturdy and meant to last. It could also indicate a desire to destroy something or take something apart. Look at the context of the dream and how the hammer was used to determine which way to interpret the hammer in your dream. Alternatively, a hammer could be used as a crude weapon. So dreaming of a hammer could indicate that you are feeling unsafe and are in need of protection.